Tolerana® improves the conception rate of inseminated cows

Fertility or reproductive efficiency is the most important component of production efficiency on bovine production systems. The economic value of cows reproductive efficacy were 3.24 bigger than other consume characteristics, indicating the importance of reproductive on bovine maternal herds system productivity (MELTON, 1995). Tolerana® is an innovated product that can help on this context, it acts mediating physiologic events of the maternal pregnancy recognition and maternal immune tolerance (communication between embryos and endometrium), that results in reduction of loss pregnancy or improve the embryo mortality prevent in mammals, resulting in great improvement of conception rate in cows. The goal of this project was to compare the conception rate of inseminated cows distributed in 02 groups (Treated and Control), considering that comparison was always done within each herd. In that way, breed, nutritional score and TFAI protocols are not influence factors on comparative conception rate between groups. Beef cows were used in test (n=7000 Nelore breed cows, average score 3 and with 75 days post-partum in average), distributes in 16 different herds and 250 Holstein cows (1 herd, average score 2.5 and 28kg/day of average milk production). The treatment was always randomly distributed and sequential within each pen of synchronized cows (1 was treated, another not, and successively until finish with that group). Statistical analyses were based on T-Test, using a linear model (pregnancy/non pregnancy) within each category (beef/dairy), using SAS System 6.9. Factors like breed, herd and category were not considered in this statistical model. The recommended dose of Tolerana® was 200µg/cow in one administration. The product was filled into 0.25mL French semen straw. The administration of Tolerana® was performed just after AI gun removal, in which another gun was passed through the cervix and the product was deposited on the uterine lumen. Preliminary results showed a gain of 9.4 percent points conception rate of beef cows, and 11.94 percent points in dairy cows. The average conception rate was 46.2% for Control Group and 55.6% for Treated Group. In dairy cows the average conception rate was 22% (Control Group) and 33.94% (treated Group). There are other ongoing experiments, looking for maximal optimization of the product, that is still at experimental stage and registration (MAPA); and thus not commercially available yet. However, with these results it appears that Tolerana® has an enormous potential – with a great impact in bovine reproduction; minimizing costs related to AI implementation and contributing to the genetic progress in bovine herds.